Uakari

Uakari (, ) is the common name for the New World monkeys from the genus Cacajao. Both the English and scientific names are believed to have originated from indigenous languages.

The uakaris are unusual among New World monkeys in that the tail length (15–18 cm) is substantially less than their head and body length (40–45 cm). Their bodies are covered with long, loose hair but their heads are bald. They have almost no subcutaneous fat, so their bald faces appear almost skull-like. Like their closest relatives the saki monkeys, they have projecting lower incisors. These monkeys have the most striking red facial skin of any primate. Females choose their mates based on how red the male's face is. Evidence suggests that the red facial coloration reflects the health of the primate.